1. Field of the Invention
The present invention relates to a DC/DC converter for controlling an output voltage.
2. Background Art
Conventional DC/DC converters include a converter which uses an inductor to boost an input voltage and output the boosted voltage (e.g., see Japanese Patent Laid-Open No. 2005-218166).
The conventional DC/DC converter stores energy in its inductor when its switching transistor is on. When the switching transistor is off, the converter superimposes the energy on the input voltage and extracts the superimposed voltage at its output. Therefore, the converter is a circuit which allows extracting the output voltage higher than the input voltage.
An output current depends on a current supplied from the inductor, and a change in the output current determines the output voltage.
A divided voltage obtained by dividing the output voltage with a voltage dividing resistance is fed back to an input of an error amplifier. The divided voltage and a reference voltage, which is generated from the input voltage, are maintained to be equal by controlling a switching element based on a signal outputted from a driver.
Thereby, the output voltage is controlled to be constant. Thus, the output voltage depends on the voltage dividing resistance and the reference voltage.